Question

If a2+b2+ c2=154 and ab+ bc +ca= -5 Find a+ b+c​

Answer 1

Answer:

${(a + b + c)}^{2} = {a}^{2} + {b}^{2} + {c}^{2} + 2(ab + bc + ca) \\ {(a + b + c)}^{2} = 154 + 2( - 5) \\ = 154 - 10 \\ = 144 \\ (a + b + c) = \sqrt{144} \\ a + b + c = 12$

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